Deflecting catheters, also referred to as steerable catheters are used in a variety of medical and non-medical procedures. In diagnostic and therapeutic medical procedures, a steerable catheter provides an operator (e.g., physician) with the ability to articulate the distal tip of the catheter in order to travel through constrained and/or tortuous anatomy, and/or to direct the distal catheter tip in a particular direction. Similar mechanisms are used in medical and nonmedical endoscopes to steer them to a target site and to orient a device portion (e.g., including a camera or other visualization means) in a desired direction.
In a typical design, control wires are manipulably attached at a proximal end of the device, and also attached at or near a distal end of the device. Such a configuration operates by manipulating one or more of the control wires to increase and/or decrease a generally longitudinal force on the distal device end that will deflect it in a desired direction. In order to prevent a premature or undesired deflection of the device, it is necessary to provide a balanced starting tension between the proximal and distal ends of the control wires. Various mechanisms in the art have been developed for doing this including threaded tensioning bolts or pins that include an aperture transversely through a head and/or shaft for receiving a proximal end portion of one or more control wires, which can then be tightened or loosened in order to provide a desired tensioning level of the control wire(s). These mechanisms often are mounted to a shaft or housing of the steerable device.
It is be desirable to provide tensioning means that provide finely tunable tensioning for very small diameter fibers, where the tuned/tensioned fibers will be secure in order to provide predictable and desirable steering behavior for a steerable catheter, and particularly for a steerable cholangioscope or other small-diameter endoscope, including providing highly-secure proximal-end anchoring of the fibers to/within the control handle.